Keggin结构磷钨钒杂多阴离子柱撑水滑石的合成、表征与热稳定性研究  

STUDIES ON SYNTHESIS, CHARACTERIZATION AND THERMAL STABILITIES OF LAYERED DOUBLE HYDROXIDES PILLARED WITH KEGGIN TUNGSTOVANADOPHOSPHATE HETEROPOLYANIONS

作　　者：郭军[1] 孙铁[1] 沈剑平[1] 刘继广[1] 蒋大振[1] 闵恩泽[1] 

机构地区：[1]吉林大学化学系

出　　处：《无机化学学报》1995年第2期134-139,共6页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金

摘　　要：采用水浴液中阴离子直接交换法合成了具有不同钒含量的Ｋｅｇｇｉｎ结构磷钨钒杂多阴离子ＰＷ（１２－ｎ）ＶｎＯ（４０）（ｎ＝１—５）柱撑水滑石，用元素分析、ＸＲＤ和ＩＲ对柱撑产物的组成和结构进行了表征．ＸＲＤ结果给出柱撑产物的底面间距达１．４７Ｍ．ＤＴＡ结果表明柱撑产物的热稳定性高于水滑石前驱体，且与杂多阴离子中Ｖ含量相关．由不同温度下焙烧样品的ＸＲＤ和ＩＲ研究可知，柱撑产物的热分解过程为：＜２５０℃时脱除物理吸附水和层间水；２５０～４００℃范围内脱羟基（同时伴随着层间Ｋｅｇｇｉｎ离子结构的破坏）；４００℃以上生成ＷＯ３和Ｍｇ２Ｖ２Ｏ７，后者在７５０℃以上分解为ＭｇＯ和Ｖ２Ｏ５．Layered double hydroxides(LDHs) pillared with heteropolyanions (POMs), PW(12-n)VnO(40)(n=1-5), were synthesized by using of direct anion exchange reaction in aqueous solution, and were charcterized by clemental analysis, XRD and IR spectra. The XRD patterns give the d001value of 1.47nm. DTA results show that the thermal stabilities of the pillared products arehigher than that of the LDH precucsor, and these values have slightly deercased with the V contents in the heteropolyanions increasing from 1 to 5. DTA combined with XRD and IR studies of samples calcincd at different temperatures shows that the thermal decomposition of the samples takes place as following: the elimination of water molecules from the interlayer space (less than 250C ); the climination of the hydroxyl groups from the brucite-like layers (between 250 to 400℃), then, WO3 and Mg2V2O7 are obtained, latter decomposes to yield MgO and V2O5 upon calcination at 7500℃.

关 键 词：杂多阴离子 柱撑水滑石 热稳定性 磷 钨 钒 

分 类 号：O641.4[理学—物理化学] O643.36[理学—化学]